1. Field of the Invention
The present invention relates to a conveying apparatus of a semiconductor device manufacturing system. More particularly, the present invention relates to a conveying apparatus having a rail section that connects semiconductor manufacturing apparatus and provides a conveying route for transferring articles used for manufacturing the semiconductor devices.
2. Description of the Related Art
With the current widespread usage of computers in information media, semiconductor memory devices are being rapidly developed to provide semiconductor devices having a high memory storage capacity and operating speed. To this end, current semiconductor technology is focused on developing and realizing memory devices having a high degree of integration, response speed, and reliability.
Semiconductor devices are manufactured by sequentially carrying out several processes including a film-forming process, a pattern-forming process, and a metal line-forming process. In carrying out these processes, articles including a wafer and a carrier for supporting the wafer are frequently conveyed in a semiconductor manufacturing system. Accordingly, a conveying apparatus for conveying these articles has been developed.
In the early stages of the semiconductor manufacturing industry, a conveying apparatus was implemented for conveying articles between semiconductor manufacturing apparatus that performed the manufacturing processes in sequence. Then, as the semiconductor manufacturing industry became more advanced, an automatic manufacturing facility was developed for manufacturing the semiconductor devices. The automatic manufacturing system was configured in a bay, including several intrabays in which the processing apparatus were laid out and an interbay that ran between the intrabays. Accordingly, a conveying apparatus was developed for use with this layout of an automatic manufacturing system. More specifically, a conveying apparatus comprising an auto guided vehicle (AGV) was developed to convey the articles throughout the automatic manufacturing system.
Recently, an over-head transfer (OHP) apparatus has been used to convey the articles along with an auto guided vehicle in an automatic manufacturing system. The over-head apparatus is mainly used to convey wafers having a diameter of 300 mm. The over-head transfer apparatus includes a series of rails installed on the ceiling of the bay and a vehicle running along the rails.
Examples of conveying apparatus that are composed of rails and a vehicle adapted to travel therealong are disclosed in U.S. Pat. No. 4,624,617 (issued to Belna), U.S. Pat. No. 5,417,537 (issued to Miller), and Korean Patent laid-open publication No. 88-10483.
An over-head transfer apparatus can be classified as an over head hoist type or an over head shuttle type according to the position in which the articles are conveyed. The over-head hoist type of conveying apparatus transfers the articles while the articles are hanging downwardly from the rails and is mainly used in the intrabay. The over-head shuttle type of conveying apparatus transfers the articles while the articles are supported upwardly on the rails and is mainly used in the interbay.
The vehicle of either type of over-head transfer apparatus runs along the rails as driven by a reusable battery or a magnetic levitated force. Since a vehicle driven by a magnetic levitated force does not generate particles, it is widely used in semiconductor manufacturing facilities. As an example, U.S. Pat. No. 4,624,617 discloses a conveying apparatus in which a magnet is installed on rails, and a vehicle is levitated by the magnet.
The wafers used in the semiconductor manufacturing industry have increased in size, from those having a diameter of 200 mm to those having a diameter of 300 mm. Accordingly, an over-head transfer apparatus has been designed for use in a bay of an automatic manufacturing system for processing wafers having a diameter of 300 mm. In this case, an over-head hoist type of conveying apparatus is installed in the intrabay and an overhead shuttle type of conveying apparatus is installed in the interbay.
Nonetheless, the routing of the over-head hoist type of conveying apparatus and the over-head shuttle type of conveying apparatus can overlap. Because the over-head hoist type of conveying apparatus conveys the articles while the articles are hanging downwardly and the overhead shuttle type of conveying apparatus conveys the articles the articles are facing upwardly, a serious problem is created when the installation routes of the conveying apparatus are duplicated.
If the installation routes are duplicated, the over-head hoist type of conveying apparatus and the over-head shuttle type-of conveying apparatus must be installed at different positions within essentially the same space. For this reason, the conveying route must be expanded and the space required to separately accommodate both the over-head hoist type of conveying apparatus and the over-head shuttle type of conveying apparatus is rather large.
Accordingly, using both an over-head hoist type of conveying apparatus and an over-head shuttle type of conveying apparatus gives rise to significant installation problems and space requirements. In addition, the use of both an over-head hoist type of conveying apparatus and an over-head shuttle type of conveying apparatus reduces the operating efficiency of the automatic manufacturing system.
The present invention has been developed to solve the above-described problems of the prior art and accordingly, it is an object of the present invention to provide a conveying apparatus for use in an automated semiconductor device manufacturing system, which unifies the routes along which articles are conveyed.
Another object of the present invention is to provide a conveying apparatus that can be easily installed in a bay of an automatic manufacturing system.
Another object of the present invention is to provide a conveying apparatus that can convey articles in various manners in a bay of an automatic manufacturing without occupying a large amount of space in the bay.
To achieve these objects, the present invention provides a conveying apparatus comprising a conveying rail section including a first rail providing a first conveying route along which upwardly facing articles used for manufacturing semiconductor devices can be conveyed, a second rail providing a second conveying route along which downwardly hanging articles can be conveyed, and intermediate rail structure by which the first and second rails are integrated.
The conveying apparatus also comprises at least one over-head shuttle type of transfer vehicle that runs along the first rail of the conveying rail section, and an over-head hoist type of transfer vehicle that runs along the second rail of the conveying rail section.
The conveying rail section includes a first rail section, that may be disposed adjacent a plurality of the processing apparatuses of the semiconductor device manufacturing system, a second rail section juxtaposed with the first rail section, and cross rails connecting ends of the first rail section to ends of the second rail section, such that a continuous loop for circulating the vehicles is formed.
The first rail of the conveying rail section is disposed at the top of the conveying rail section and extends horizontally, parallel to the ground when installed, and the second rail is disposed at the bottom of the conveying rail section and extends parallel to the first rail. The first and second rails are connected to each other by an intermediate rail structure in the form of a beam that is oriented vertically between the centers of the bottom surfaces of the first and second rails.
The first vehicle includes a first support for the articles and a first running portion that runs along the first rail. The first running portion extends from both sides of the bottom of the first support to both sides of the bottom surface of the first rail and is in surface-contact with the intermediate rail structure of the conveying rail section. The second vehicle includes a second support from which articles can hang and a second running portion that runs along the second rail. The second rail extends from both sides of the top of the second support to both sides of the bottom (upwardly facing) surface of the second rail and is in surface-contact with the intermediate rail structure of the conveying rail section.
The first support includes a plate and a wall that projects from the periphery of the plate to prevent articles from falling off of the plate while the articles are being conveyed. The second-support includes a flange configured to receive a member by which articles can be suspended from the flange. Both vehicles have guide wheels for guiding the vehicles along the respective rails.
At least one vehicle of the vehicle section may be a magnetically levitated (mag-lev) vehicle. For example, a plurality of magnets for generating a magnetic levitating force may be provided at an upper portion of the conveying rail section in a line parallel to the ground. A third vehicle operated by the magnetic levitating force is provided on the conveying rail section.
The conveying apparatus includes the first rail, the first vehicle running along the first rail, the second rail integrated with the first rail, and the second vehicle running along the second rail, to unify the conveying routes in the bay. The conveying apparatus can be installed in the bay without occupying a large amount of space. Accordingly, an automatic manufacturing system for processing wafers having a diameter of 300 mm can be effectively achieved.